Photoinduced Surface Activation of Semiconductor Photocatalysts under Reaction Conditions: A Commonly Overlooked Phenomenon in Photocatalysis
Xiaoping Tao, Wenwen Shi, Bin Zeng, Yüe Zhao, Na Ta, Shengyang Wang, Abraham Adenle, Rengui Li, Can Li
Abstract
Solar-driven water splitting by photocatalysts is potentially a promising solution for global-scale production of nonfossil fuels and environmental problems, yet deep understanding toward the intrinsic active sites and activity of photocatalysts under real photocatalytic conditions is still insufficient. Here, taking bismuth tantalum oxyhalogen (Bi4TaO8X) as an example, we unraveled a commonly overlooked phenomenon of photoinduced surface activation, in which the intrinsic active sites generated and dominated the enhanced photocatalytic activity under reaction conditions. We demonstrated that a thin layer of amorphous tantalum oxides species was in situ generated on the surface of the Bi4TaO8X photocatalyst at the initial stage of the photocatalytic reaction, and such amorphous species were proven to be the active sites which can significantly facilitate the photocatalytic water-splitting reactions. The investigation focusing on photoinduced surface activation of photocatalysts under the reaction conditions not only unravels the reactive states of semiconductor photocatalysts but also sheds light on the understanding of photocatalytic mechanisms.